--- /dev/null
+From b5663ba405fe3e51176ddb6c91a5e186590c26b5 Mon Sep 17 00:00:00 2001
+From: NeilBrown <neilb@suse.de>
+Date: Tue, 31 Mar 2009 14:39:38 +1100
+Subject: [PATCH] md/raid5: simplify interface for init_stripe and get_active_stripe
+
+Rather than passing 'pd_idx' and 'disks' to these functions, just pass
+'previous' which tells whether to use the 'previous' or 'current'
+geometry during a reshape, and let init_stripe calculate
+disks and pd_idx and anything else it might need.
+
+This is not a substantial simplification and even adds a division.
+However we will shortly be adding more complexity to init_stripe
+to handle more interesting 'reshape' activities, and without this
+change, the interface to these functions would get very complex.
+
+Signed-off-by: NeilBrown <neilb@suse.de>
+---
+ drivers/md/raid5.c | 43 ++++++++++++++++++++++---------------------
+ 1 file changed, 22 insertions(+), 21 deletions(-)
+
+--- linux-2.6.27-SLE11_BRANCH.orig/drivers/md/raid5.c
++++ linux-2.6.27-SLE11_BRANCH/drivers/md/raid5.c
+@@ -276,8 +276,9 @@ static int grow_buffers(struct stripe_he
+ }
+
+ static void raid5_build_block (struct stripe_head *sh, int i);
++static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks);
+
+-static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks)
++static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
+ {
+ raid5_conf_t *conf = sh->raid_conf;
+ int i;
+@@ -292,11 +293,11 @@ static void init_stripe(struct stripe_he
+
+ remove_hash(sh);
+
++ sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
+ sh->sector = sector;
+- sh->pd_idx = pd_idx;
++ sh->pd_idx = stripe_to_pdidx(sector, conf, sh->disks);
+ sh->state = 0;
+
+- sh->disks = disks;
+
+ for (i = sh->disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+@@ -332,10 +333,12 @@ static struct stripe_head *__find_stripe
+ static void unplug_slaves(mddev_t *mddev);
+ static void raid5_unplug_device(struct request_queue *q);
+
+-static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks,
+- int pd_idx, int noblock)
++static struct stripe_head *
++get_active_stripe(raid5_conf_t *conf, sector_t sector,
++ int previous, int noblock)
+ {
+ struct stripe_head *sh;
++ int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
+
+ pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
+
+@@ -363,7 +366,7 @@ static struct stripe_head *get_active_st
+ );
+ conf->inactive_blocked = 0;
+ } else
+- init_stripe(sh, sector, pd_idx, disks);
++ init_stripe(sh, sector, previous);
+ } else {
+ if (atomic_read(&sh->count)) {
+ BUG_ON(!list_empty(&sh->lru));
+@@ -2481,8 +2484,7 @@ static void handle_stripe_expansion(raid
+ conf->raid_disks -
+ conf->max_degraded, &dd_idx,
+ &pd_idx, conf);
+- sh2 = get_active_stripe(conf, s, conf->raid_disks,
+- pd_idx, 1);
++ sh2 = get_active_stripe(conf, s, 0, 1);
+ if (sh2 == NULL)
+ /* so far only the early blocks of this stripe
+ * have been requested. When later blocks
+@@ -3412,8 +3414,10 @@ static int make_request(struct request_q
+ for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
+ DEFINE_WAIT(w);
+ int disks, data_disks;
++ int previous;
+
+ retry:
++ previous = 0;
+ prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
+ if (likely(conf->expand_progress == MaxSector))
+ disks = conf->raid_disks;
+@@ -3428,9 +3432,10 @@ static int make_request(struct request_q
+ */
+ spin_lock_irq(&conf->device_lock);
+ disks = conf->raid_disks;
+- if (logical_sector >= conf->expand_progress)
++ if (logical_sector >= conf->expand_progress) {
+ disks = conf->previous_raid_disks;
+- else {
++ previous = 1;
++ } else {
+ if (logical_sector >= conf->expand_lo) {
+ spin_unlock_irq(&conf->device_lock);
+ schedule();
+@@ -3447,7 +3452,8 @@ static int make_request(struct request_q
+ (unsigned long long)new_sector,
+ (unsigned long long)logical_sector);
+
+- sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));
++ sh = get_active_stripe(conf, new_sector, previous,
++ (bi->bi_rw&RWA_MASK));
+ if (sh) {
+ if (unlikely(conf->expand_progress != MaxSector)) {
+ /* expansion might have moved on while waiting for a
+@@ -3582,9 +3588,7 @@ static sector_t reshape_request(mddev_t
+ for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
+ int j;
+ int skipped = 0;
+- pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks);
+- sh = get_active_stripe(conf, sector_nr+i,
+- conf->raid_disks, pd_idx, 0);
++ sh = get_active_stripe(conf, sector_nr+i, 0, 0);
+ set_bit(STRIPE_EXPANDING, &sh->state);
+ atomic_inc(&conf->reshape_stripes);
+ /* If any of this stripe is beyond the end of the old
+@@ -3632,10 +3636,7 @@ static sector_t reshape_request(mddev_t
+ if (last_sector >= (mddev->size<<1))
+ last_sector = (mddev->size<<1)-1;
+ while (first_sector <= last_sector) {
+- pd_idx = stripe_to_pdidx(first_sector, conf,
+- conf->previous_raid_disks);
+- sh = get_active_stripe(conf, first_sector,
+- conf->previous_raid_disks, pd_idx, 0);
++ sh = get_active_stripe(conf, first_sector, 1, 0);
+ set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ release_stripe(sh);
+@@ -3725,9 +3726,9 @@ static inline sector_t sync_request(mdde
+ bitmap_cond_end_sync(mddev->bitmap, sector_nr);
+
+ pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);
+- sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);
++ sh = get_active_stripe(conf, sector_nr, 0, 1);
+ if (sh == NULL) {
+- sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
++ sh = get_active_stripe(conf, sector_nr, 0, 0);
+ /* make sure we don't swamp the stripe cache if someone else
+ * is trying to get access
+ */
+@@ -3793,7 +3794,7 @@ static int retry_aligned_read(raid5_con
+ /* already done this stripe */
+ continue;
+
+- sh = get_active_stripe(conf, sector, conf->raid_disks, pd_idx, 1);
++ sh = get_active_stripe(conf, sector, 0, 1);
+
+ if (!sh) {
+ /* failed to get a stripe - must wait */
projects / people / pmueller / ipfire-2.x.git / blobdiff